Abstract: Biological control by conservation of native natural enemies can help to reduce theneed for pesticides and prevent their detrimental effects upon the environment. Here we assessthe role of ground-active generalist predators as natural enemies of two tortricid pests in appleorchards. Using diagnostic PCR on the gut of field-caught ground-active predators, we found nodifference in predation rates on these two pests. Spiders were the most efficient predators ofmoths in spring while the carabid beetles, feeding on diapausing larvae, were important inautumn. The temporal complementarity between spiders and carabid beetles highlights the needfor diverse predator assemblages to optimize conservation biological control.